Interpretive Summary: Very small particles of chitosan, an ingredient in seafood shells, were added to cellulose, a component of wood, films. These particles were then examined under very powerful microscopes. The particles were found to improve the strength and barrier properties of the films. They were located in the pores in the films.

Technical Abstract:
Chitosan/tripolyphosphate nanoparticles were prepared and incorporated in hydroxypropyl methylcellulose (HPMC) films. FT-IR and transmission electron microscopy (TEM) analyses of the nanoparticles, mechanical properties, water vapor permeability, thermal stability, scanning electron microscopy (SEM) of the films were analyzed. Incorporation of chitosan nanoparticles in HPMC films improved their mechanical and barrier properties significantly. The chitosan nanoparticles tend to occupy the empty spaces in the pores of the HPMC matrix, increasing the collapse of the pores and thereby improving film tensile properties and water vapor permeability. The thermal stability of the films increased by the addition of nanoparticles. This study demonstrates that using chitosan/tripolyphosphate nanoparticles improves physical properties of HPMC films.